N-aryl ureas

ABSTRACT

N-(3-CHLORO - 4 - TRIFLUOROMETHYL-PHENYL)-N&#39;&#39;-ALKYL AND -N&#39;&#39;,N&#39;&#39;-DIALKYL-UREA WHICH POSSESS HERIBICIDAL PROPERTIES AND WHICH MAY BE PRODUCED BY CONVENTIONAL METHODS.

nited States Patent Int. Cl. C07c 127/18 US. Cl. 260-553 A 3 Claims ABSTRACT OF THE DISCLOSURE N-(3-chloro 4 trifluoromethyl-phenyl)-N-alkyl and -N',N'-dialkyl-urea which possess herbicidal properties and which may be produced by conventional methods.

The application is a continuation of application Ser. No. 747,486, now abandoned.

The present invention relates to and has for its objects the provision for particular new N-aryl ureas which possess valuable, especially selective, herbicidal properties, active compositions in the form of mixtures of such compounds with solid and liquid dispersible carrier vehicles, and methods for producing such compounds and for using such compounds in a new way, especially for combating weeds, undesired plants, and the like, with other and further objects becoming apparent from a study of the within specification and accompanying examples.

It is known that certain N-aryl-N'-alkyl ureas can be used as herbicides. It is further known specifically that N-(3-trifluoromethyl-phenyl)-N',N'-dimethyl urea (A) and N-(4-trifluoromethyl-phenyl)-N',N'-dimethyl urea (B) can be used as selective herbicides (see British Pat. 914,779).

It has now been found, in accordance with the present invention, that the particular new N-aryl ureas, i.e. N-(3- chloro-4-trifluoromethyl phenyl)-N'-alkyl and N,N- dialkyl-ureas, having the general formula in which R, is selected from the group consisting of hydrogen and alkyl having 1-4 carbon atoms, and R is alkyl having l-4 carbon atoms, exhibit strong herbicidal, in particular selective herbicidal, properties.

It has been furthermore found, in accordance with the present invention, that a versatile and smooth process for the production of the particular new N-aryl ureas of Formula I above in favorable yields may be provided, which comprises reacting 3-chloro-4-trifiuoromethyl-phenyl isocyanate having the formula C Fa-QNC 0 in the presence of the solvent with an amine having the formula Ra (11b) in which R and R are the same as defined above.

3,792,089 Patented Feb. 12, 1974 It is very surprising that the ureas of the present invention, compared to the previously known ureas, possess a better selectivity, with the same or higher herbicidal activity.

In this regard, when dimethyl amine is used, the course of the production reaction can be represented by the following equation:

(III) The 3-chloro-4-trifluoromethyl-phenyl isocyanate starting material can be prepared according to known processes.

Examples of suitable amines include methyl, dimethyl, methyl-butyl and isopropyl amine, and the like.

As solvent (this term includes mere diluents) water and inert organic solvents are suitable. These include ethers, such as dioxane and tetrahydrofuran, aromatic hydrocarbons, such as chlorobenzene.

The reaction temperatures can be varied within a fairly wide temperature range; they are normally substantially between about '0 to 0., preferably from about 20 to 40 C.

In carrying out the reaction, equimolar amounts of the starting materials may be used. An excess of amine does not harm the reaction. The working up of the reaction mixture may take place in the usual manner.

The particular new N-aryl ureas of the present invention exhibit strong selective herbicidal properties. These compounds can therefore be used for the control of weeds in crops. The instant compounds are particularly useful for the control of weeds in cereal crops, such as wheat, barley and maize.

The present invention is especially concerned with control of weeds which grow in cereals. Examples of weeds which occur in cereals and which are difficult to control but which are destroyed by the particular new active compounds of the present invention include dicotyledons, such as common chickweed (Stellaria media), mayweed (Matricaria chamomilla), ivy-leaved speedwell (Veronica heaerifolia), knotgrass (Polygonum avz'cultrre), dead nettle (Lamz'um pec.) and monocotyledons, such as silky bentgrass (Apera Spica: venti) and annual bluegrass (Poa annua).

The selectivity of the instant new ureas in cereals is a genuine selectivity. It occurs not only when the present ureas are applied according to the pre-emergence method but also when they are used according to the post-emergence process, that i when the herbicide is contacted directly with the cereal plants.

The selectivity of the instant new ureas in cereals is surprising, because chemically quite, similar compounds which are already known show, with similar herbicidal potency, no selectivity in cereals.

The active compounds according to the instant invention can be utilized, if desired, in the form of the usual formulations or compositions with diluents or extenders, i.e. dispersible carrier vehicles, such as solutions, emulsions, suspensions, emulsifiable concentrates, spray powders, pastes, soluble powders, dusting agents, granules, etc. These are prepared in known manner, for instance by extending the active compounds with dispersible liquid diluent carriers and/or dispersible solid carriers optionally with the use of carrier vehicle assistants, e.g. surface-active agents, including emulsifying agents and/or dispersing agents, whereby, for example, in the case where water is used as diluent, organic solvents may be added as auxiliary solvents (cf. Agricultural Chemicals, March 1960, pp. 35-38). The following may be chiefly considered for use as carrier vehicles for this purpose: dispersible liquid diluent carriers including inert organic solvents, such as aromatic hydrocarbons (for instance, benzene, toluene, xylene, etc.), halogenated, especially chlorinated, aromatic hydrocarbons (for instance, chlorobenzenes), paraffins (for instance, petroleum fractions), chlorinated aliphatic hydrocarbons (for instance, methylene chloride, etc.), alcohols (for instance, methanol, ethanol, propanol, butanol, etc.), ethers, ether-alcohols (for instance, glycol monomethyl ether, etc.), amines (for instance, ethanolamine, etc.), amide (for instance dimethyl formamide, etc.), sulfoxides (for instance, dimethyl sulfoxide, etc.), ketones (for instance, acetone, etc.), and/or water; as well as dispersible inert finely divided solid carriers, such as ground natural minerals (for instance, kaolins, alumina, silica, chalk, i.e. calcium carbonate, talc, kieselguhr, etc.), and ground ynthetic minerals (for instance, highly dispersed silicic acid, silicates, e.g. alkali silicates, etc.); whereas the following may be chiefly considered for use as carrier vehicle assistants, e.g. surface-active agents, for this purpose: emulsifying agents, such as nonionic and/or anionic emulsifying agents (for instance, polyethylene oxide esters of fatty acids, polyethylene oxide ethers of fatty alcohols, alkyl sulfonates, aryl sulfonates, etc., and especially alkyl arylpolyglycol ethers, magnesium stearate, odium oleate, etc.); and dispersing agents, such as lignin, sulfite waste liquors, methyl cellulose, etc.

As will be appreciated by the artisan, the active compounds according to the instant invention may be employed alone or in the form of mixtures with one another and/or with such solid and/or liquid dispersible carrier vehicles and/or with other known compatible active agents, especially plant protection agents, such as other herbicides, fungicides, insecticides, bactericides, etc., if desired, or in the form of particular dosage preparations for specific application made therefrom, such as solutions, emulsions, suspensions, powders, pastes, and granules which are thus ready for use.

As concerns commercially marketed preparations, these generally contemplate carrier composition mixtures in which the active compound is present in an amount substantially between about 0.1 and 95% by weight, and preferably 0.5 and 90% by weight, of the mixture, whereas carrier composition mixtures suitable for direct application or field application generally contemplate those in which the active compound is present in an amount substantially between about 0.01 and 2.0%, preferably 0.01 and 0.8%, by weight of the mixture. Thus, the present invention contemplates over-all compositions which comprise mixtures of a dispersible carrier vehicle such as (l) a dispersible carrier solid, and/ or (2) a dispersible carrier liquid, such as an inert organic solvent and/or water, preferably including a surface-active effective amount of a carrier vehicle assistant, e.g. a surface-active agent, such as an emulsifying agent and/or a dispersing agent, and an amount of the active compound which is effective for the purpose in question and which is generally between about 0.01 and 95%, by weight of the mixture.

While the active compound can be used according to the pre-emergence method, i.e. before emergence of the cultivated plants, they are particularly efiective also when used according to the post-emergence method.

Generally, the amounts of active compounds used for actual application to the agricultural area may be varied within fairly wide ranges, such as for example substantially between about 0.1-5 kg. of active compound per hectare, preferably between about 0.5-3 kg./hectare. Of course, where the active compound is used in admixture with a carrier vehicle, the content of active compound in the composition mixture actually applied is, in general, substantially between about 0.1 and 2%, and preferably between about 0.2 and 0.8%, by weight of the mixture as aforesaid, yet the mixture is applied such that the active compounds are used in said amounts between about 0.1-5 kg./hectare.

The inventive compositions also can be used by the so-called ultra-low-volume process with good success. In this process it is possible to use formulations containing up to of active ingredients or even the active substance alone.

Furthermore, the present invention contemplates methods of selectively controlling or combating undesired plants, e.g. weeds and the like, which comprise applying to at least one of (a) such weeds and (b) their habitat, i.e. the locu to be protected, a herbicidally effective amount of the particular active compound of the invention alone or together with a carrier vehicle as noted above. The instant formulations or compositions are applied in the usual manner, for example, by spraying, atomizing, scattering, dusting, watering, sprinkling, and the like, whether for pre-emergence application to the soil or post-emergence application to the weeds.

It will be realized, of course, that in connection with the pro-emergence use of the instant compounds as well as the post-emergence use thereof, the concentration of the particular active compound utilized alone or in admixture with the carrier vehicle will depend upon the intended application and may be varied within a fairly wide range depending upon the weather conditions, the purpose for which the active compound is used, and the plants which are to be controlled or protected. Therefore, in special cases, it is possible to go above or below the aforementioned concentration ranges.

The following examples illustrate, without limitation, the herbicidal activity of the particular active compounds of the present invention.

EXAMPLE 1 Post-emergence test/ outdoors/ spray powder Inert carrier material: 0.25 parts by Weight kaolin and silicic acid (3: 1)

Protective colloid: 0.03 parts by weight lignin sulfate Dispel-sing auxiliary: 0:15 parts by weight hydroxyarylsulfonic acid formaldehyde condensate To produce a suitable preparation of the particular active compound, 1 part by Weight of such active compound was mixed with the stated amounts of formulation auxiliaries and the resulting concentrate was then diluted with water to the desired final concentration.

Outdoor plots with test plants which had a height of about 3-10 cm. were sprayed with such an amount of the given active compound preparation that a uniform wetting of the plants occurred. The amount of active compound applied per unit area is decisive. After three Weeks the degree of damage to the plants was determined and characterized by the values 0-5, which have the following meaning:

0 no effect 1 a few slightly burnt spots 2 marked damage to leaves 3 some leaves and part of stalks partially dead 4 plant partially destroyed 5 plant completely dead The particular active compounds tested, the amounts used and the results obtained can be seen from the following Tables 1a and 1b.

TABLE la Post-emergence test-Outdoor Concentration of Matri- Polyactive com- Apera caria Veronica gonum Stelpound, spice Poa chamohederiawz'cu' Lamium laria Active compound kg./ha. Wheat Barley semi annua milla falia lure spec. media 2 2 2 a 2 2 5 5 4 4 NHC-N\ CH: CF

(known) i. P i 2 2 2 2 g l: 5 2

3 5 era-@qvn-e-r:

(known) (11L)... CH; 2 1 1 5 5 5 5 5 5 ll 1 0 0 5 5 5 4.5 4.5 5 5 CF: NH-C-N TABLE 1b Post-emergency test-outdoors Concentration of active compound, Earth Port- Ama- Cheno- Active compound kgJha. Cotton nuts ulacca rantus podium (A)-..-- O CH; 2 1.5 4 5 5 5 1 1.0 a 5 5 5 NHON\ l CH OF: (k

own (B).....; 0 CH: 2 2.5 3 5 5 5 1 1.5 2.5 4.5 5 5 CF NH-O-N CH: (known) (1111).... Q CHa 2 0 O 5 5 5 ll 1 0 0 a 5 5 CFa NHCN\ CH3 Cl EXAMPLE 2 centration of the active compound in the preparation is of no importanceonly the amount of active compound apn r s ra 0 de Pre emerge ce test/outdoo s/ p y p w r phe d per mm area 18 declslve Inert carrier material: 0.25 parts by weight kaolin and silicic acid 3 1) Protective colloid: 0.03 parts by weight lignin sulfate Dispersing auxiliary: 0.15 parts by weight hydroxyarylsulfonic acid formaldehyde condensate To produce a suitable preparation of the particular active compound, 1 part by weight of such active compound was mixed with the stated amount of formulation auxiliaries and the resulting concentrate was then diluted with water to the desired final concentration.

Shortly after the sowing of the test plants outdoors, the individual plots were watered with such an amount of the given active compound preparation as was necessary for a uniform wetting of the surface of the soil. The con- After 5 weeks, the degree of damage to the test .plants was determined and characterized by the values 0-5, which have the following meaning:

0 no effect 1 slight damage or delay in growth 2 marked damage or inhibition of growth 3 heavy damage and only deficient development or only 50% emerged 4 plants partially destroyed after germination or only 25% emerged 5 plants completely dead or not emerged The particular active compounds tested, the amounts used and the results obtained can be seen from the following Tables 29. and 2b.

TABLE 2a Pro-emergence test-Outdoor Concentration of active Stel- Polycompound, Poa laria gonum Matricaria Lamiu'm Active compound kgJha. Wheat Barley Maize 012mm media avzculare chamomilla spec (A)....- O OH: 2 4 3 3 6 5 3.5 5 5 l 1 a a 2 4 4.5 2 4 4 -NHON\ CHI CF:

(known) (B)-..... O CHI 2 5 4.5 3.5 5 5 4.5 5 5 1 4.5 3.5 a 5 5 4 4 4 CF: NHC-N\ CHI (known) (I113) CH1 2 0 0 5 4. 5 5 5 1 0 0 0 5 5 4 4 4 CF: NH-C-N\ TABLE 23 Pro-emergence Text-Outdoor Concentration 0! active compound, Earth Port- Ama- Cheno- Active compound kgJha. Cotton nuts ulacca rantus podium (A) O CH; 2 1.5 3 5 5 5 H 1 1 2 5 4.5 5 NHCN\ CH; CF:

(known) (B)....-. 0 CH; 2 2 3 5 5 5 II 1 1 2 4.5 4.5 5 CF NHC-N\ (known) 111 O CH; 2 0 0 5 5 5 ll 1 0 o 5 4.5 5 CF; NHC-N CH3 Cl EXAMPLE 3 just dew moist. After three weeks, the degree of damage posbemergence test to the plants 1s determined and characterized by the values 0-5, WhlCh have the following meaning:

Solvent: 5 parts by weight acetone Emulsifier: 1 part by weight alkylaryl polyglycol ether Test plants which have a height of about 5-15 cm. are

sprayed with the given active compound preparation until 0-no effect 1--a few slightly burnt spots 2-rnarked damage to leaves 3--some leaves and parts of stalks partially dead 4plant partially destroyed 5plant completely dead t The particular active compounds tested, their concentrations and the results obtained can be seen from the following Table 3.

TABLE 3 Post-emergence test Concentration of active compound Stel- Galin- Active compound in percent Wheat Barley Cotton laria soga Sinapis (A) CH1 0. 05 3 3 2 5 5 5 0. 025 2 2 1 4. 5 4. 5 5 NH-C-N CH3 Fa (known) (B) 0 CH; 0. 05 4 4 3 4. 5 5 5 1|: 0. 025 3 3 1. 5 4. 5 4.5 5 C F. N H N\ (known) (III CH; 0. 05 1 0 0 5 5 5 ll 0. 025 0 0 0 5 5 5 C F NH-C-N (1V1) (III) /C HI 0. 05 O O 5 5 5 C F NH-C-N (V1)--'.-.': 0 0.05 0 0 O 5 5 5 g 0.025 0 0 0 4.5 4 5 5 0 Fa NH- NHCH;

EXAMPLE 4 3 5 the amount of active compound applied per umt area Pie-emergence test Solvent: 5 parts by weight acetone Emulsifier: 1 part by weight alkylaryl polyglycol ether To produce a suitable preparation of the particular active compound, 1 part by weight of such active compound is mixed with the stated amount of solvent, the stated amount of emulsifier is added and the resulting concentrate is then diluted with water to the desired final concentration.

Seeds of the test plants are soon in normal soil and, after 24 hours, watered with the given active compound preparation. It is expedient to keep constant the amount of water per unit area. The concentration of the active compound in the preparation is of no importance, only being decisive. After three weeks, the degree of damage to the test plants is determined and characterized by the values 0-5, which have the following meaning:

0 0 no elfect The particular active compounds tested, the amounts applied and the results obtained can be seen from the following Table 4.

TABLE 4 Pro-emergence test Concentration of active compound Stel- Galin- Active compound kg./ha Wheat Barley Cotton laria soga Slnapis (A) 0 CH: 2 2 2. 5 2 5 5 5 g 1 1 1. 5 1 5 4. 5 5 NH- N CHI Fa (known) (B)-..::: O CHI 2 3 3 2. 5 5 5 5 It 1 2 2 2 4. 5 5 5 CF: NH- --N\ CHa (known) (III|)...:: CH: 2 0 5 0 0 5 5 5 V 1 1 0 0 5 5 5 TABLE 4-Continued Concentration of active compound Stel- Galin- Active compound in percent Wheat Barley Cotton laria soga Sinapls (V2) 0 H; 2 0 0 o 5 5 5 a 1 o 0 o 5 4.5 5 CF: NH- -N\ (Va) O 2 0 0 0 V 5 5 5 a 1 0 0 0 4.5 4.5 5 CF NH- -NH-CH| The process for producing the particular new compounds of the present invention is illustrated, without limi- CF! NHCONHCH: tation, by the following further examples.

1 (VI) EXAMPLE 5 M.P. 143C.

0 F NH O O N(CH3):

EXAMPLE 7 (i) Preparation of 3-chloro-4-methyl-phenyl isocyanate To a solution of 450 g. phosgene in 1.5 liters benzene there is added dropwise at 0-5 C. a solution of 425 g. 3-chloro-4-methyl aniline in 1.75 liters chlorobenzene. While introducing phosgene, the mixture is heated to 120 C., a clear solution forming after about 1 hour. By distillation there are obtained 356 g. of the above isocyanate, i.e. 3-ch1oro-4-methyl-phenyl isocyanate, of B.P. 113- 114 C./20 mm. Hg.

(ii) Preparation of 3-ch1oro-4-trichloromethyl-pheny1 isocyanate 690 g. 3-chloro-4-methyl-phenyl isocyanate are chlorinated under ultra-violet irradiation for 8 hours at 180- 200 C. A weight increase of about 300 g. is obtained. The desired 3-chloro-4-trichloromethyl-phenyl isocyanate boils at B.P. 173174 C./16 mm. Hg. Yield: 618 g.

(iii) Preparation of 3-chloro-4-trifluoromethyl-phenyl isocyanate 136 g. 3-chloro-4-trich1oromethyl-phenyl isocyanate are added dropwise within about 2 hours at 0 C. to 150 ml. hydrogen fluoride. After stirring for several hours until the cessation of evolution of HCl, the hydrogen fluoride is distilled oif in a vacuum. The crystalline residue is distilled at 120 C. under nitrogen. Yield: 77 g., B.P. 93 C./ 14 mm. Hg.

EXAMPLE 6 In the same manner as described for the production of N (3 chloro-4-trifluoromethyl-phenyl)-N',N'-dimethylurea in Example 5 the following compounds are obtained:

(IVs) M.P. 78 C.

Using corresponding molar amounts of each of the following amines with 3-chloro-4-trifluoromethyl-phenyl isocyanate in accordance with the procedure of Example 5, as the case may be:

(a) tert.-buty1 amine and 3-chloro-4-trifluoromethylphenyl isocyanate;

(b) di-isopropyl amine and 3-chloro-4-trifluoromethylphenyl isocyanate; and

(c) methyl-n-butyl-amine and 3-chloro-4-trifluoromethylphenyl isocyanate;

the corresponding final compounds, respectively, are produced:

(a) N-(3-chloro-4-trifluoromethyl-phenyl)-N'-tert.-butylurea;

(b') N-(3-chloro-4-trifluoromethyl-phenyl) -N',N-diisopropyl-urea; and

(c) N-(3-chloro-4-trifluoromethyl-phenyl)-N'-methyl- N'-n-butyl-urea.

Advantageously, in accordance with the present invention, in the foregoing formulae:

R represents hydrogen; or alkyl having 1-4 carbon atoms,

such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert.-butyl, and the like, particularly C alkyl; and

R represents alkyl having 1-4 carbon atoms, as defined above, such as methyl to tert.-buty1 inclusive, and the like, particularly C alkyl.

In accordance with a particular feature of the present invention, R represents hydrogen or the same C especially C alkyl as R It will be realized by the artisan that all of the foregoing compounds contemplated by the present invention possess the desired selective or total herbicidal properties, and especially the capability of selectively destroying weeds, as well as a comparatively low toxicity toward warm-blooded creatures and a concomitantly low phytotoxicity with respect to higher plants, enabling such compounds to be used with correspondingly favorable compatibility with warm-blooded creatures and higher plants for more eifective control and/or elimination of weeds by selective application of such compounds to such weeds and/or their habitat. Nevertheless, the instant compounds possess total herbicidal action when used in large quantities, although selective herbicidal action is obtained when 13 used in smaller quantities. As contemplated herein, the term weeds is meant to include not only weeds in the narrow sense, but also in the broad sense, whereby to cover all plants and vegetation considered undesirable for the particular purposes in question.

It will be appreciated that the instant specification and examples are set forth by Way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention which is to be limited only by the scope of the appended claims.

What is claimed is:

1. N-(3-chloro-4 trifluoromethyl pheny1)-N',N'-dimethyl-urea.

1 2. N (3-chloro 4-triflnoromethyl-phenyl)-N',N-diethyl urea.

3. N-(3-chloro-4 trifluoromethyl phenyl)-N'-methyl- N'-n-butyl-urea.

References Cited UNITED STATES PATENTS 3,177,249 4/1965 Martin et a1. 260553 X 0 HOWARD T. MARS, Primary Examiner M. W. GLYNN, Assistant Examiner US. Cl. X.R. 

